Permission Error when creating/writing a file using a python program in Ubuntu

Question

I'm walking through a tutorial on how to analyze data for a climate model. It has you download files from a NASA database that have data from prior runs of the model, and then in a virtual environment specifically made for analysis of this data, has you use a series of python 3.12 programs to do so. The first step is converting fort.11* files into netCDF4 files, and it gives you this command:

MarsFiles.py fort.11* -fv3 fixed average daily diurn

fort.11* having 5 different variations and this command splitting each of them up into two dozens netCDF4 files. The issue is, when I run this command, it tells me

PermissionError: [Errno 13] Permission denied: b'/home/user/AmesCAP/CAP_tutorial/INTERTCLDS/07180.fixed.nc

07180.fixed.nc is one of the files it's supposed to create and write into as a result of analyzing any of the fort.11* files. It stops here and doesn't create or write into any other files like it should. I've tried changing permissions both inside and outside the virtual environment, but nothing changes. I'm not really sure what to do if it can't write into something that it creates while running. I can't use the python programs outside of the virtual environment, either; ubuntu doesn't recognize them outside it. Is this a result of it being in a virtual environment, or am I missing something? I'm quite new to this so any advice is greatly appreciated!